Abstract
The averaged electroretinogram (ERG) and visual evoked potential (VEP) from the superficial Wulst were recorded in 3 adult cormorants under anesthetized conditions. Furthermore, some anatomical characteristics of the cormorant's brain were briefly described.
1) The outline of the cormorant's telencephalon in shape was very similar to that of the crow which has the conspicuously developed Wulst.
2) The a-wave of the ERG in the adult cormorant showed maximum amplitude at 20 to 80 joule stimulation. While the amplitude of the c-wave increased with increasing flash intensities, the amplitude of the b-wave was maximum at 2 joule.
3) The averaged VEP from both the scalp and the surface of the Wulst were reliably obtained by 0.3 to 80 joule flash stimulation. At 20 joule stimulation, the VEP consisted of a few positive-negative notches with very small amplitide which was followed by two major negative deflections. The peak latencies of the two negative deflections were 40-50msec and 96-140msec, respectively. The amplitude of the VEP of the Wulst region was higher from the skull (150-250μV) than from the scalp (ca. 50μV).
